In recent years, high precision purification or removal of a specific protein is emphasized in medical and pharmaceutical fields. For example, in order to purify a chemical having a specific function, it is necessary to purify a specific protein highly precisely.
In affinity chromatography, protein A having a specific binding property as a ligand is widely used. Protein A is a protein originating from gram-positive Eubacteria Staphylococcus, specifically binds to the Fc regions of IgGs from various animals, and is widely used to purify IgG. A technique has been widely known in which the protein A is immobilize to an insoluble carrier, and by affinity chromatography using the insoluble carrier, IgG is specifically isolated and purified.
In an affinity carrier employed for affinity chromatography, usually, a structure called linker is interposed between the insoluble carrier and the ligand, and one end of the linker is bonded to the carrier and the other end of the linker is bonded to the ligand, to immobilize the ligand to the insoluble carrier (Patent Document 1).
Patent Document 2 proposes chromatography with an improved dynamic capacity and with a higher flow rate in a shorter residence time, by a solid phase carrier suitable for application to affinity chromatography, containing silica particles having pore sizes larger than 630 Å and smaller than 1,000 Å and having an average particle size larger than 55 μm and smaller than 70 μm. However, in Patent Document 2, the pressure loss tends to increase if the average silica particle size is decreased so as to increase the amount of the silica particles packed, and if the pressure loss is high, the upper limit of the linear flow rate may be restricted.